In the pneumatic tire art, it is known that, as the tread of the tire wears away, the ability to maintain traction may diminish on wet or snow-covered roads. Accordingly, once the tread is worn beyond a certain tread depth, the tire should be replaced to maintain adequate traction.
In order to inform a vehicle user when a tire may need to be replaced due to tread wear, prior art tread wear indicators were developed. For example, some tread wear indicators involved providing features molded in the base of the circumferential grooves of the tire tread. However, such tread wear indicators may undesirably interfere with the flow of water and materials through the groove. In addition, due to their placement in a groove, they may be difficult for a user to see.
Other indicators were developed, which we located in the tread elements of the tires. However, many such prior art indicators have undesirably interfered with tread performance and/or were difficult for a user to see. An additional disadvantage of prior art indicators that were disposed in the tread is that the indicators were of a simple configuration which wore away before the user saw or understood the wear indication.
Still other indicators were developed that involve sensors which measure tire wear and provide an alert or signal to the user as to the wear state of the tire. While such sensors are suitable for their intended purpose, they add to the cost of the tire.
As a result, there is a need in the art for a tread wear indicator for a pneumatic tire that is easy for a user to see, does not interfere with groove or tread element performance, and is economical to form.